What Was Pilot Thomas Mantell Chasing When His Plane Crashed in 1948?

Balloon, UFO, or something else? Questions remain over one of the most famous--and tragic--UFO incidents of the 1940s

Another of the classic UFO cases that have taken root in the annals of government investigations into sightings of anomalous things in our skies is the case of Kentucky Air National Guard pilot Captain Thomas F. Mantell. He is often described as the first known military pilot to have perished while in pursuit of a UFO. Those familiar with the story will doubtless have seen many television productions describing the tale, along with depictions in books and magazine articles.

The basic details of the story have been frequently recounted in UFO-related literature. An unusual object was seen in the skies above Godman Field at Fort Knox, Kentucky, on January 7, 1948, spanning a period from 2:40 pm central time until 4:00 pm and beyond. Other reports claim that a similar object was seen hours earlier, and possibly even after the intercept. What is known is that multiple personnel at Godman Field at Fort Knox, Kentucky saw something large and unusual in the sky above their location. At that time, the C Flight of the 165th Fighter Squadron, Air National Guard, composed of four P-51 Mustangs under the command of Captain Thomas F. Mantell was flying from Marietta, Georgia to Standiford Field, Kentucky in Louisville. They were on a routine training mission when the tower personnel at Godman Field asked them to divert and investigate the unidentified object that had been seen over the airfield. 

At that point, Mantell and two of the other pilots in his squadron diverted to Godman Field to search for the UFO that had been reported. The fourth pilot continued on to Standiford Field. At this point, the ensuing events become the subject of contentious debate, but there is a comprehensive body of evidence found in government documents that allow us to provide a closer examination of these events. What is known beyond any question is that Thomas Mantell did not survive his encounter with whatever anomalous object he was dispatched to investigate.

Mantell incident
A P-51D Mustang, similar to the one flown by Mantell in 1948 (Photo credit: National Museum of the Air Force).



There are many reports of this event containing the same descriptions and sensationalized reports of Mantell dying in pursuit of a UFO. Sadly, most of them are heavy on drama but short on verifiable facts. There is one video that was published just last year that purports to be a documentary-style report of the incident.


We invite readers to watch the 9-minute production primarily because almost every detail of the event (with a few exceptions) is totally unsupported and in many cases flatly contradicted by the original source materials from Project Blue Book and the Air Force’s investigation into what happened. The same is true of many other supposed documentaries reporting on this event. Locations, depictions of the UFO in question, reports from witnesses and pilots… they are all riddled with errors. Also, the source material itself, involving testimony from multiple primary witnesses, is contradictory in places and requires serious examination to separate the wheat from the chaff. What’s not in dispute, however, is that something remarkable happened and the military, along with other government agencies, took a great deal of interest in it.

In order to come closer to the truth, The Debrief will examine the original government records of the investigation discovered through the FOIA process by John Greenewald jr. at The Black Vault and compare them to the popular culture depictions of the story. The linked trove of government documents is nearly 100 pages long and includes numerous reports from Project Blue Book over the course of a lengthy investigation.



Reports created from Project Blue Book interviews with numerous people who were witnesses to these events at various stages are included in our analysis. We will first identify the key witnesses who will be referenced here. The first group is composed of military personnel who were in or around the control tower at Godman Field and who observed the unknown object.

  • Captain J.F. Duesler Jr. (Operations Officer)
  • Lt Colonel E.Garrison Wood
  • Commanding Officer Colonel Hix
  • Detachment Commander Lt. Paul I. Orner
  • Technical Sgt. Quinton A. Blackwell, Control Tower Chief Operator
  • Private First Class Stanlay Oliver

Additional interviews included in this analysis were conducted with civilians and law enforcement personnel from the region. There is also testimony from the surviving pilots.

As to what the object reportedly looked like, there is a perhaps surprising amount of consistency between the accounts of the witnesses. Captain Duesler described it as being shaped “like a teardrop, round.” PFC Oliver said it resembled “an ice cream cone topped with red.” Lt. Orner described it as being shaped “like a parachute, round, with some red lights around the bottom.” Mantell’s wingman, a pilot named Clements, described it as appearing “like the reflection of sunlight on an airplane canopy.”

With the exception of Clements, all of the witnesses described something that was generally round at one end, coming to a point at the other. Teardrops, ice cream cones, and parachutes would all fit that description.

As to the size of the object, there were also similarities. Duesler told investigators that it was “large, at least several hundred feet in diameter. Mantell himself radioed the tower and said the object was “metallic and of tremendous size.” TS Blackwell, the control tower operator, simply described it as “tremendous.” Three other witnesses estimated the size to be between 250 and 300 feet.



The ensuing investigation revealed reports of what the investigators believed or at least suspected was the same object from a number of locations in two states. A close examination of all of these witness reports reveals what appears to be several instances of either typographical errors or mispronunciations of the names of towns and even roads. For example, references are made of a sighting at the same time in Kentucky over “Mansville,” and “Maysville” as well as “Madisonville,” despite the fact that two of the locations are more than 100 miles apart. All of them seem to be misunderstandings of the name of Madisonville, Kentucky. But examining all of them in context leads us to believe that most of the sighting locations and times can be identified.

It is also worth noting that if this object was in fact a craft operated by extraterrestrials, they may have been guilty of PWI (piloting while intoxicated). The reports describe a long and winding path.

The first report comes in at 7:20 am over Edwardsville, Illinois, northeast of St. Louis, more than 200 miles away from Godman Field. The next reports offer conflicting times of either 1:00 pm or 1:10 over Elizabethtown, located south by southeast of Godman. Shortly after that, at either 1:20 pm or 1:30 pm, an unnamed citizen called police reporting a “cone-shaped object” (again consistent with previous descriptions) over Madisonville. The witness also estimated it to be between 250 and 300 feet in size.

By 2:00 pm the object was reported over Irvington, Kentucky (also reported as “Irvine” which was likely a typo), roughly ten miles west of Godman field and simultaneously over Owensboro, 63 miles to the west, and “Maysville.” In this portion of the Blue Book report, the sightings attributed to both Owensboro and Maysville had lines drawn through the names.

That brings us to 2:30 pm when the object is first sighted over Godman Field at Fort Knox.

Photo credit: Google Maps



Perhaps somewhat ironically, while there is some confusion and debate over the flight path of the object prior to the incident at Fort Knox, the one area where we have the most verifiable information involves the locations and activities of Captain Thomas F. Mantell himself, with the unfortunate exception of one critical moment. There is little to no disagreement from the witnesses about his role in the day’s events with some minor exceptions regarding his wording when speaking to the control tower. There was also one witness who thought Mantell’s squadron consisted of five planes instead of four and another who only recalled seeing three. That latter number is easily explainable, however, as we shall cover here.

Mantell was leading his squadron of four P-51 Mustangs on a routine training flight en route from Marietta, Georgia heading to Standiford Field, Kentucky in Louisville. Standiford is only a short distance to the northeast of Fort Knox and Mantell’s flight path would take him almost directly over Godman Field.

By the time the squadron was approaching Godman at approximately 4:00 pm, the sighting of the object had been going on for ninety minutes. The tower at Godman radioed and asked Mantell’s squadron to divert and investigate the sighting. Three of the planes, one being Mantell’s (NG869), another flown by his wingman pilot named Clements (NG800), and a third flown by a pilot named Hammond (NG737) diverted to Godman Field to investigate. The fourth plane, piloted by an officer named Hendrichs, continued on to Standiford. 

The pilots saw the object at a higher altitude above the field and began climbing to approach it. Reaching 22,000 feet, Hammond announced that he either didn’t have oxygen equipment or had run out of oxygen and couldn’t go higher so he would need to return to Standiford and land. Unfortunately, at this point, the reports of the witnesses diverge in one potentially significant way.



In one version of the report (found on page 26 of the linked archive), Hammond and Clements then turned back to land at Standiford to refuel while Mantell continued to climb in pursuit of the object. After refueling, Clements flew back to Godman and climbed to 32,000 feet but could not locate either the object or Mantell’s plane. He returned again to Standiford. At 5:50 pm the tower at Sandiford advised that Mantell’s plane had crashed at approximately 4:45 pm in the town of Franklin, Kentucky.

But in the report filed by Detachment Commander Lt. Paul I. Orner, only Hammond turned back after announcing he was out of oxygen. Clements continued to follow Mantell in pursuit of the object up until the point where Mantell sends his last radio transmission, saying that he’s

“closing in to take a good look.” After that, Clements (NG800) radios that Mantell’s plane has “disappeared” but he could still see the object. At that point, Mantell had been above 25K altitude while Clements was at 20k. Clements then returns to Standiford to refuel before returning to search unsuccessfully for Mantell and the object.

Both accounts end the same way. After “disappearing,” Mantell’s plane crashed into the yard of a Mrs. Carrie Phillips who lived on Lake Spring Road, 5 miles Southwest of Franklin, Ky on the W.J. Phillips farm. There is no record of what happened that caused Mantell’s plane to come down. The Flight Service Center contacted Police Officer Joe Walker in Franklin who had taken charge of the crash site. He reported that when he arrived, Mantell’s body “had been removed from the aircraft.” (It was likely ejected at some point.) Eyewitnesses told the officer that they had seen the plane coming down nose-first in a steep dive and that the plane had either “exploded” or “disintegrated” in the air before striking the ground. The craft did not burn up after impact. The wreckage was reportedly spread out for over a mile and the tail section, the propeller, and one wing were not initially located.

Reports of when the tower last had radio contact with Mantell vary, but it seems to have been between 4:15 and 4:30 pm. The crash of Mantell’s plane in Franklin, Kentucky took place at approximately 4:45 pm according to civilian witnesses. That means that the plane traveled more than 90 miles to the south with a presumably unconscious or deceased pilot before performing a high-speed nosedive toward the ground, either “exploding” or ” disintegrating” in midair high above the wreckage site.

Meanwhile, airfields from St. Louis, Coffeyville, Kansas, Fort Smith, Arkansas, and Kansas City, Missouri reported sightings of a “great ball of light” that they were tracking heading West by Southwest at 250 miles per hour.

In April of 1948, Air Materiel Command at Wright-Patterson sent a request to the Flying Safety Division at Langley Air Force Base requesting a copy of the accident report on Mantell’s crash. The request specifically indicated that the report would be used in an intelligence study with respect to Project “SIGN.” (Page 41 of the linked archive.)

In a sad coincidence, Franklin, Kentucky was the town where Thomas Mantell was born and raised before joining the military. It was almost as if his faithful P-51 had “brought him home” to his final resting place. A plaque erected in his honor remains there to this day. 

Mantell Incident
Historical marker near the site of the Mantell incident (photo credit: YouTube).



Over the course of the Blue Book investigation, multiple letters from Air Material Command at Wright-Patterson Air Force Base were sent out requesting all meteorological records from the region on the day in question. They also asked astronomers to identify the positions of both Venus and Jupiter in the sky on an hourly basis. They definitely seemed to be looking for any mundane explanation, but even their own investigation found that those planets would not be visible during daylight hours and the weather was good for visibility. 

Given the specific, nearly identical descriptions of the size and shape of the object provided by multiple witnesses, the idea that everyone involved had simply misidentified a star or planet should be easily ruled out. The slow speed and size of the object have led some to suggest it may have been a blimp or perhaps a skyhook balloon. These balloons were developed in the 1940s and the general shape could be a good fit for the “teardrop” shape described by witnesses. But Mantell and the other pilots drew fairly close to the object. Would they not have been able to identify a balloon?

As for what happened to Mantell, investigators concluded that he became hypoxic after flying higher than 20,000 feet. This does not explain how pilot Clements was able to climb to 33,000 feet in the same model P-51 when he returned to continue the search, however. That’s also well below the maximum rated altitude of the P-51 Mustang. A later report from Orner confirmed that

Clements did obtain a fresh supply of oxygen while refueling, so perhaps Mantell ran out without realizing it. 

Some popular documentaries on the Mantell crash seemed to suggest that his plane came down shortly after encountering the object. This has led to the suggestion that it had taken some sort of offensive action against him. But as noted above, Mantell’s plane flew more than 90 miles before crashing, presumably without a conscious pilot controlling it.

Would that have happened to a plane with an unconscious or deceased pilot at the controls? A look at the flight controls of the P-51 doesn’t make that entirely clear. But a view of the center stick control column in the cockpit and how the pilot’s body is oriented, along with the position of the pilot’s hand on the controls offers some clues. If the pilot were to become unconscious or die, their hand would almost certainly drop off of the stick. The pilot’s harness would prevent the body from leaning forward onto the stick. With no hand on it, the Mustang’s center stick would spring back to the default position of orienting the plane for steady forward movement at a constant altitude.

Provided the plane was oriented toward the south when Mantell was disabled and there was sufficient fuel left in the tank, it’s not difficult to see how the aircraft could have flown to Franklin, Kentucky before the engine died. Would the plane have then gone into a steep nosedive? Well, the P-51 is a very “nose-heavy” aircraft.

There is still no “smoking gun” in terms of what actually happened to Thomas Mantell in the final moments when he approached the unidentified object. Nor are we left with a definitive conclusion as to what the object was. It remains in the eye of the observer to debate whether this was a mundane case of a pilot running out of oxygen while investigating an escaped test balloon or one of the few suspected “dogfights” between a military pilot and a potentially extraterrestrial craft where the aliens gained the upper hand.

Rest in peace, Captain Mantell… you’ve left us all quite the mystery to ponder.